A known form of bogey includes a body with a pair of wheels at either end, on fixed wheel axles. The bogey carries a hanger bolt or the like, which is mounted perpendicularly to the body by being screw threaded into the body. The hanger bolt in turn supports a hinge which is attached to a folding panel such as a door or window panel.
The bogey is designed to travel in an overhead track and strict tolerances between the wheels and the track need to be satisfied in order to avoid wear or fatigue of component parts as the bogey passes along the track and variable moment forces are applied to the wheels and hanger bolt, as the panel moves between an open and a closed condition.
Height adjustment of the hanger bolt relative to bogey is required to hang a hinge for a folding door or panel at a correct height relative to an overhead track. A head of the hanger bolt supports a hinge leaf, which in turn carries the folding door, and a shank of the hanger bolt is screw threaded into and out of the body of the bogey to achieve the required height adjustment of the hanger bolt and supporting hinge.
A lock nut, mounted on the threaded shank of the hanger bolt, has previously been used to lock the hanger bolt against the body of the bogey, in order to prevent further vertical movement once the correct height has been achieved. However, over time and multiple door folds, a lock nut can loosen and cause the door to drop.
Another mechanism for fixing the height of the hinge is to lock the hinge leaf to the hanger bolt head. This may be achieved using a spring biased tab in the head of the hanger bolt to releasable lock into a slot formed in the hinge leaf. However, the machining of such a mechanism is non-trivial and any further adjustment is difficult as the tab needs to be held in a retracted condition during adjustment. Importantly though, repeated rotation of the hanger bolt in the body of the bogey as the door is opened and closed, may wear the thread.